1. Field of the Invention
The invention refers to an aggregate for a washing machine with a plastic sudsing container made of a fiber glass reinforced polymeric material and consisting of a front and a rear wall held together by a shell or circularly bent wall, with a hollow cylindrical drum disposed within the sudsing container for rotation about a horizontal or inclined axis and with a bearing seat for the cantilevered bearing of the drum by receiving a shaft connected therewith. Moreover, the invention relates to a method of making an aggregate for a washing machine with a plastic sudsing container made of a fiber glass reinforced polymeric material and consisting of a front and a rear wall held together by a shell or circularly bent wall, with a hollow cylindrical drum disposed in the sudsing container for rotation about a horizontal or inclined axis and with a support structure in the area of one of the front and rear walls having in its center a bearing seat for the cantilevered bearing of the drum by receiving a shaft connected therewith.
2. The Prior Art
Washing machines with an aggregate in which the sudsing container is made of stainless steel are known, for instance, from German laid-open patent specification DE-OS 27 19 336. Stainless steel sudsing containers are also use in washing machines made and sold by the assignee of the instant invention. For their cantilevered bearing, the containers are provided with a shaft which is received by two spaced-apart bearings. The two bearings are arranged in a sleeve-like bearing seat. In the mentioned washing machines, a supporting cross made of cast iron is provided for mounting and retaining the bearing seat on the sudsing container. The support or bearing cross including the bearing seat and sudsing container are manufactured as separate components which are later assembled by screws or clamping rings.
For some time now polymeric materials, usually fiber glass reinforced, has been used for the manufacture of sudsing containers. Washing machines with polymeric sudsing drums are known, for instance, from European patent specifications 0 043 429 A1 and 0 374 519 A2 and German patent specification DE 298 21 140 A1. In the known washing machines it is customary to use a cylindrical bearing housing made of metal (usually it is a milled cast iron structure) as the bearing seat and during manufacture of the sudsing container bottom to coat it by injection of a polymeric material. From German patent specification DE 100 40 319 C1 it is also known to forego a metal bearing seat and to coat the bearings by injection of a polymer. Variants in which a support cross is separately made and mounted on the sudsing container, as is the case with stainless steel sudsing containers, are not known and are not useful since, for reasons to be explained hereinafter, the connecting points are subjected to high loads which could result in breaking of the polymer.
German laid-open patent specification DE-OS 199 60 501 A1 discloses a sudsing container of polymeric material and provided with a cylindrical bearing housing. The bearing housing is provided with an additional rotationally symmetric collar for receiving and mounting a stator of a direct drive. However, the injected polymer extends only to the outer margin or outer end of the collar. Since the bearing housing with its integrated stator support component are of small diameter, it transmits very large forces to the rear wall of the sudsing container which needs to be compensated by relatively involved structural means such as reinforcing ribs. Also, heat dissipation of the bearing is not optimal, so that large temperature peaks and differences in temperature within the rear wall of the suds container are possible.
At nowadays common spinning revolutions of up to 1,800 min−1, friction in the area of the bearings may result in heat generation of temperatures in the range of about 100° C. In known aggregates with polymeric suds containers, such generated heat is dissipated either through the bearing housing or directly to the bottom of the suds container. This may damage the material and loosen the connection between the metal and polymeric material. At imbalances caused by a non-symmetric distribution of laundry in the drum, the high revolutions also generate high flexural forces which are diverted to the bottom of the suds container by way of the bearings. This may also damage the bottom itself or its connection with the bearing housing as well as the curved wall or shell of the suds container.
German laid-open patent specification DE-OS 102 16 517 A1 discloses a method of manufacturing a sudsing vat made of polymeric material. Mechanical components are placed into an injection mold and inserted into the suds container by injection-coating. For the precise and reliable placement of the mechanical operational components other measures are required, however.